Reinstatement of Memecylon elegantulum (Melastomataceae) and recircumscription of Memecylon rostratum, two species endemic to Sri Lanka

$¢PhytoKeys

PhytoKeys 259: 67-80 (2025)
DOI: 10.3897/phytokeys.259.146534

Research Article

Reinstatement of Memecylon elegantulum (Melastomataceae)
and recircumscription of Memecylon rostratum, two species
endemic to Sri Lanka

Amila Perera’?®, Himesh Jayasinghe®*®, Bhathiya Gopallawa*®, Isuru Madawala’™®,
Nimal Gunatilleke®®, Nalaka Geekiyanage”®

N DOD oo FP WO YH —

Postgraduate Programme, Faculty of Agriculture, Rajarata University of Sri Lanka, Anuradhapura 50000, Sri Lanka
Dilmah Ceylon Tea Company PLC, No 111, Negombo Road, Peliyagoda, 11830, Sri Lanka

National Institute of Fundamental Studies, Hantane Road, Kandy 20000, Sri Lanka

Postgraduate Institute of Science, University of Peradeniya, Peradeniya 24000, Sri Lanka

Agriculture Publication Unit, Department of Agriculture, Gannoruwa, Peradeniya 20400, Sri Lanka

Department of Botany, Faulty of Science, University of Peradeniya, Peradeniya 24000, Sri Lanka

Department of Plant Sciences, Faculty of Agriculture, Rajarata University of Sri Lanka, Anuradhapura 50000, Sri Lanka

Corresponding author: Amila Perera (sperera.amila@gmail.com)

OPEN Qaceess

Academic editor: Marcelo Reginato
Received: 25 January 2025
Accepted: 22 May 2025

Published: 19 June 2025

Citation: Perera A, Jayasinghe

H, Gopallawa B, Madawala |,
Gunatilleke N, Geekiyanage N
(2025) Reinstatement of Memecylon
elegantulum (Melastomataceae)
and recircumscription of Memecylon
rostratum, two species endemic

to Sri Lanka. PhytoKeys 259:

67-80. https://doi.org/10.3897/
phytokeys.259.146534

Copyright: © Amila Perera et al.
This is an open access article distributed under
terms of the Creative Commons Attribution

License (Attribution 4.0 International - CC BY 4.0).

Abstract

Memecylon elegantulum Thwaites, a heterotypic synonym of M. rostratum Thwaites, is
re-instated based on recent collections and field observations. The two species differ
mainly in their habit, inflorescence structure, floral morphology and lamina morphology.
A lectotype and an epitype are designated for Memecylon elegantulum, and a lectotype
designated for M. rostratum. Both species are confined to the mixed dipterocarp rainfor-
ests of Sri Lanka's perhumid south-western ‘wet zone’. Memecylon elegantulum appears
to be restricted to a relatively small range in Ratnapura district, while M. rostratum has a
wider distribution in wet zone.

Key words: Endemic, low land wet zone, Sri Lanka, typification

Introduction

The genus Memecylon L. is the largest genus of the subfamily Olisbeoideae,
one of the three subfamilies in Melastomataceae (Christenhusz et al. 2018;
Penneys et al. 2022). This genus consists of shrubs and trees usually with pin-
nately veined leaves of opposite arrangement and comparatively small flowers
(Bremer 1979). While Renner et al. (2022) considered the genus to comprise
more than 350 species, POWO (2024) estimates it to be substantially richer,
and new species continue to be reported in substantial numbers (Stone 2022,
2023). The genus is distributed across the Old-World tropics, from Africa to
Australia, including South and Southeast Asia (Maxwell 1980; Bremer 1987;
POWO 2024), with many of the species exhibiting restricted distributions
(Stone 2012; POWO 2024).

67

Amila Perera et al.: Status of Memecylon elegantulum

Having originated in Africa in the Eocene, Memecylon appears to have dispersed
to South Asia through long-distance dispersal events (Amarasinghe et al. 2021).
Being a continental island that was frequently connected to India by the Palk Isth-
mus during sea ice ages since the Miocene (Pethiyagoda and Sudasinghe 2021),
however, the lineages of Memecylon in Sri Lanka are closely related to those of
India. The latest revision of the genus for Sri Lanka (Bremer 1987) recognized 32
species (28 of them being endemic), distributed throughout the island, from the
strongly seasonal arid zone to the perhumid wet zone, ranging from near sea level
to the highest peaks over 2000 m in elevation. Recent discoveries of range exten-
sions of some species from South India (Viswanathan and Rajendran 1993; Viswa-
nathan 1995; Murugan and Manickam 2001; Kumar et al. 2004; Rajendraprasad et
al. 2006; Ayyappan et al. 2012; Sivu et al. 2012; Udhayavani and Ramachandran.
2013), however, have reduced the number of endemics, calling for a critical review
of earlier literature. The latest checklist (Wijesundara et al. 2020) considered 26 of
the 32 species are endemic to Sri Lanka. Studies of Memecyion in Sri Lanka pre-date
Linnaeus, who coined the generic name for two species collected from the island,
by Paul Hermann in 1670s (Linnaeus 1753). Trimen (1894) considered Memecylon
to be ‘one of the most difficult genera in Sri Lankan flora’, adding that the genus
probably contained additional species in the island. Bremer (1979) too, mentioned
that the material available to him was insufficient to fully understand the species al-
ready described and hence, to describe new species. Due to the lack of specimens
and the poor condition of material available at the time, Bremer (1979) provision-
ally synonymized Memecylon elegantulum Thwaites under Memecylon rostratum
Thwaites, retaining this synonymy also in his revision of the genus (Bremer 1987).

Recent field work in Sri Lanka’s wet zone has served to improve our under-
standing of the distribution and morphology of M. rostratum and its heterotypic
synonym, M. elegantulum. It is clear from the material now at hand that M. ele-
gantulum is a distinct species. We therefore reinstate this name, stabilizing its
identity through the designation of a lectotype and an epitype. In this article, we
provide diagnoses, descriptions and illustrations of both species.

Materials and methods

Fieldwork was conducted during 2023 and 2024. Non-typical Memecylon ros-
tratum was first encountered in Walankanda Forest Reserve in the Sinharaja
Forest complex, in January 2023, during a floristics survey under Endane Biodi-
versity Corridor Project to understand the compositional variation of threatened
flora along an elevation gradient. While georeferencing other species, special
attention was paid to search for the taxon also in nearby forests. Throughout
this period, data on both typical and non-typical Memecylon rostratum were
gathered, including distributional range, morphological variability, and associ-
ated microhabitats. See Jayasinghe et al. (2022) for methodology associated
with field collections, photography and measurements. Specimens collected
were deposited in the National Herbarium, Peradeniya (PDA); abbreviations fol-
low Thiers (2024). Additional specimens were examined in the collections of
PDA, while specimens deposited in overseas herbaria (E, L, M, PR BR, US) were
examined via JStor and the online resources available through those herbaria.
Nomenclature follows the Shenzhen code (Turland et al. 2018), while author
abbreviations and publication conventions follow IPNI (2024).

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534 68

Amila Perera et al.: Status of Memecylon elegantulum

Taxonomic treatment

Memecylon elegantulum Thwaites, Enum. Pl. Zeyl. 112 (1859); Trimen,
Handb. FI. Ceylon, 2: 214 (1894)
Figs 1,2

Memecylon rostratum auct. non Thwaites, K.Bremer, Opera. Bot. 50: 21 (1979),
p.p.; K.Bremer in Dassan., Revis. Handb. FI. Ceylon 6:224 (1987), p.p.

Type. * Sri Lanka n./., n.d., n.coll., C.P. 2684 (lectotype: third branch from the
left of PDA [PDA00002924!], designated here); Samanala Watta side of Pet-
tigala Forest Reserve, 17 iv 2023, H.Jayasinghe et al. HDJ 2097 (epitype:
PDA00109496, designated here).

Description. Memecylon elegantulum is distinguished from M. rostratum
upto 2 m tall (vs treelet, to 7 m); having flush leaves deep purple-red to light
pink (vs whitish green); branched, pedicellate inflorescence with 1-2 flowers
(vs unbranched inflorescence with 6-9 capitate flowers); petals in bud coni-
cal with an apiculate tip (vs obtuse tip); anthers and anther connectives white
(vs purplish-blue); straight anther connective without a gland (vs arched anther
connective, with a prominent red gland); and fruit hanging, pale green in imma-
ture stage (vs erect, white).

Shrubs or treelets up to 2 m height; outer bark shallowly and longitudinally
striate; young branchlets obscurely quadrangular, becoming terete with age;
flush leaves deep purple-red to light pink; internode distance 18-25 mm.
Leaves green above, much paler below, lustrous on both sides in live state,
greenish-brown in dried state; petiole 1-2 mm long; lamina subcoriaceous,
broadly to (rarely) narrowly elliptic, 40-65 x 15-20 mm, caudate to acum-
inate, obtuse at apex, narrowly obtuse to cuneate at base, margins slightly
revolute toward base, slightly thickened; midrib slightly grooved adaxially,
obscurely raised abaxially; lateral veins 7—9 pairs, with a few intermediaries,
straight throughout, unicolorous in live state, venation visible on both sides
in dried state; intramarginal vein 0.3-1 mm from the margin. Inflorescence
1 (—2) per node, axillary on lower leaf nodes or rarely below the existing leaf
nodes; main axis of the peduncle 2.5-3.5 mm long, filamentous, quadran-
gular, pale yellowish green, topped by (1—) 2 capitate secondary axils, sur-
rounded by minute bracts at the joint; secondary axils 2-3 mm long, filamen-
tous, cylindrical, pale greenish white, topped by 2, minute, whitish bracts,
holding a single flower. Flowers pedicel 4.5—5 mm long, white; hypantho-ca-
lyx broadly pyriform to infundibuliform, 1.7-—1.9 mm long, 2.3-2.5 mm wide,
outside smooth, white, sometimes with a bluish tinge at apex; calyx lobes
4, minute, obtuse to acute at apex; epigynous chamber smooth, without any
furrows; exposed petals conical with a pointed apex in bud, white at an-
thesis, reflexed, 2.4-—2.6 mm long, 1.8-2.1 mm wide; filaments 3.4-3.7 mm
long, white; anther connective straight, 2.2-2.7 mm long, 0.6-0.7 mm wide,
white; without a gland; anthers white; style 5.9-6.1 mm, white. Fruits 1-2 per
inflorescence with an elongate, hanging pedicel up to 7-8 mm; subglobose,
9.5-11 x 7.5-9 mm diameter, topped by a persistent calycinal crown; sur-
face smooth, yellowish green during immature stage, purplish blue at partial
maturity, then turning blackish purple at maturity; cotyledons wrinkled.

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534 69

Amila Perera et al.: Status of Memecylon elegantulum

~ >. X 0.25 cm

Figure 1. Memecylon elegantulum Thwaites; A. Habit; B. Branch with an inflorescence; C. Young stem; D. Lamina upper
side; E. Lamina under side; F. Dorsal view of flower; G. Inflorescence with a single flower bud; H. Inflorescence with two
flowers after anthesis; J. Lateral view of flowers; K. Two inflorescences arising from a single node; L. Bracts; M. Dorsal
view of flower bud; N. Dorsal view of epigynous chamber after anthesis; P. Lateral view of partially ripe fruit; Q. Dorsal
view of immature fruit; R. Longitudinal section of a fruit; S. Wrinkled cotyledons.

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534

Amila Perera et al.: Status of Memecylon elegantulum

Figure 2. Line drawing of Memecylon elegantulum Thwaites; A. Branch; B. Lamina under side; C. Lamina upper side;
D. Two inflorescences arising from a single node; E. Dorsal view of the flower bud; F. Lateral view of flowers; G. Dorsal
view of flower, G- inflorescence with a single flower bud, H. Bracts; J. Lateral view of partially ripe fruit; K. Dorsal view of
epigynous chamber after anthesis; L. Longitudinal section of a fruit; M. Wrinkled cotyledons.

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534 7

Amila Perera et al.: Status of Memecylon elegantulum

Distribution and habitat. Lowland rainforests of Sri Lanka, northwards to
Sinharaja Forest in the elevation range 250-800 m (Fig. 3). It usually occurs at
the lower level of the rainforest understorey, on ridges and as well as in valleys.

Phenology. Flowering and fruiting were recorded twice a year, from February
to April and from August to November.

Notes. In the protologue of Memecylon elegantulum, Thwaites (1859) briefly
described its inflorescence, flower and the fruit. All the morphological features
and distribution details he provided, except the description of the pedicel, are
consistent with our own observations. Thwaites mentioned, however, that the
pedicel was ‘as half as long as the calyx [calyce dimidio longioribus], while the
taxon described here has pedicels approximately three times long as the calyx.
Later, Trimen (1894) described the flower as sessile, which was repeated by
Alston (1931). After a thorough search in herbaria, we encountered four syn-
types. Although Trimen (1894) and Alston (1931) detailed the flower and the
fruit, the syntypes we examined contained neither flowers nor fruits except for
the crushed parts of a fruit in the pocket of BM000944509! and an immature
fruit in the pocket of PDA00002922!. Although Trimen (1894), in his enumera-
tion, mentioned that he had only scant material of this taxon, we were unable to
locate any material other than the mentioned syntypes prior to Trimen’s time.

The drawing made from C.P. 2684 by H. de Alwis, Thwaites’ draftsman
(Pethiyagoda 2007) curated at PDA, is a leafy branch with a single hanging
fruit, which is bluish purple. This species has the longest pedicel (relative to
the length of the hypanthocalyx) among the Sri Lankan species of Memecylon,
while having a unique inflorescence architecture. Given that Thwaites noted
that inflorescence was ‘sparsely racemose’ [parce ramosis], it is possible that
he was misled by this feature, thinking that the pedicel was a secondary axis of
the inflorescence. The second branch from the left of PDA00002924! has two
broken primary axils of inflorescences, highlighting its filamentous nature. The
third branch from the left of PDAQ0002924! has a single broken inflorescence
axis, including a part of the secondary axis. This inflorescence section features
the bracts at the inflorescence branching.

Since little Sri Lankan material was available to him, Bremer (1979) provision-
ally synonymized Memecylon elegantulum under M. rostratum. Bremer (1979)
lectotypified the name as ‘C.P. 2684 in PDA’ while considering C.P. 2684 in BM &
K to be iso-lectotypes. We note, however, that there are two sheets labelled C.P.
2684 in PDA, both of poor quality. As detailed by Jayasinghe et al. (2022), a single
C.P. number often included multiple gatherings. PDA00002922! has an indistinct
pencil notation about the gathering information (possibly ‘Gilimale, March 1853’)
while PDA00002924! lacks any such information. This suggests that these spec-
imens may have been the result of multiple gatherings. It is important, however,
that type specimens be from a single gathering (see Article 8.2, footnote 1). Here
under Art. 9.3, newly lectotypify the name, selecting the specimen in the best con-
dition. Since the syntpes represent multiple gatherings, they are retained as such,
without considering them for iso-lectotypification. Given that all the syntypes cur-
rently lack flowers as well as a complete peduncle, they only partially represent
the taxon. Hence, we designate a flowering specimen as an epitype (Article 9.9).

Specimens examined. Sri Lanka: » Ratnapura District: Kalawana, 30 iv 1970,
N.Balakrishnan NBK 315 (PDA, US02955738); Approximately 2 miles from Ras-
sagala, 09 xi 1975, S.H.Sohmer & S.Waas 10491 (PDA); » Bambarabotuwa Forest

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534 79

Amila Perera et al.: Status of Memecylon elegantulum

80°0'0"E 81°0'0"E 82°0'0"E
10°0'0"N 10°0'0"N
9°0'0"N es
8°0'0"N 8°0'0"N
7°0'0"N PON
arbor 6°0'0"N

0 15 30 60 90 120
82°0'0"E

80°0'0"E 81°0'0"E

Figure 3. Distribution map Memecylon elegantulum Thwaites and M. rostratum Thwaites.

Reserve, 15 v 2018, M.Gunathilake, N.Gunawardena & A.Sumanadasa NBS/2018/
BAM/071 (PDA); « ibid., 14 v 2018, M.Gunathilake, N.Gunawardena & A.Sumana-
dasa NBS/2018/BAM/023 (PDA); « ibid., NBS/2018/BAM/013 (PDA); « ibid., 06 xi
2018, B.Gopallawa & S.Gamage BAM 337 (PDA); ibid., BAM 203 (PDA); Botiya-
gala, Gilimale-Erathna forest, 21 viii 1993, A.H.M.Jayasuriya & B.W.M.Wijesinghe
7478 (PDA); * Gilimale, Gilimale-Erathna forest, 4 vii 1993, A.H.M.Jayasuriya &
B.W.M.Wijesinghe 7415 (PDA); « ibid., 27 iii 2024, H.Jayasinghe & Samarasinghe
HDJ 2922 (PDA); * Dotalugala forest, 27 viii 1976, S.Waas 1831 (PDA, L2545519,
E01411687); » Massenna forest reserve, above Rassagala estate, 25 x 1993,
A.H.M.Jayasuriya & B.W.M.Wijesinghe 7644 (PDA); « Kiribathgala forest reserve, 06
iv 2024, H.Jayasinghe, D.Samarasinghe & S.Kanishka HDJ 2961 (PDA); * Walank-
anda, 19 i 2023, H.Jayasinghe, A,Perera, I.Madawala HDJ 1947 (PDA); * Delwa-
la, 27 i 2023, H.Jayasinghe, A. Perera, I. Madawala HDJ 1956 (PDA) « Unknown
localities: s./., s.d., s.coll., s.n., C.P. 2684 (PDA00002922; remaining specimens
other than the lectotype of PDA00002924; BM000944509, KO00859185).

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534 73

Amila Perera et al.: Status of Memecylon elegantulum

Memecylon rostratum Thwaites, Enum. PI. Zeyl. 111 (1859); Trimen, Handb.
FI. Ceylon, 2: 218 (1894); K.Bremer, Opera. Bot. 50: 21 (1979), p.p.; K.Bremer
in Dassan., Revis. Handb. FI. Ceylon 6:224 (1987), p.p.

Figs 4,5

Type. + Sri Lanka n./., n.d., n.coll., C.P. 1560 (lectotype: the largest branch with
flowers [second from the left] of PDA [PDA00002923!], designated here)

Description. A small tree, to 8 m tall; outer bark smooth, not longitudinally
striate, yellowish brown; young branchlets terete; flush leaves pale yellowish
green, sometimes with a red tinge; internode distance 15-30 mm. Leaves
green above, paler below, lustrous on both sides in live state, brown on upper
side and yellow-brown on underside in dried state; petiole 2-5 mm long; lam-
ina subcoriaceous, elliptic to ovate 40-70 x 25-38 mm, caudate to acumi-
nate, obtuse to rounded at extreme apex, broadly to narrowly cuneate at base,
margins flat, rarely slightly revolute towards base; midrib adaxially slightly
grooved, abaxially obscurely raised; lateral veins 7-9 pairs, invisible in live
state, hardly visible abaxially in dried state; intramarginal vein 0.3-0.5 mm
from the margin. Inflorescence 1 (—2) per node, axillary, mainly on nodes be-
low the existing leaves and extending in to the lower leaf nodes; peduncle of-
ten unbranched, (0—)2.5-5 mm long, thick, obscurely quadrangular to terete,
green; secondary axils almost sessile when the peduncle is branched; flowers
umbellate, 3-14 flowers per inflorescence; minute bracts at the base of the
petiole early caducous, brown. Flowers pedicel 0.4-—1 cm long, white; hyp-
antho-calyx broadly infundibuliform to pyriform with an abrupt medial infla-
tion, 1.3-1.5 mm long, 1.8-2.3 mm wide, outside smooth, white; calyx lobes
4, 0.4-0.5 mm long, 1.2-1.4 mm wide, obtuse to acute at apex; epigynous
chamber smooth, without any furrows; exposed petals dome-shaped with an
apiculate apex and 4 grooves radiating from the centre of each calyx lobe,
white at anthesis, reflexed, 1.5-2 mm long, 1.2-1.6 mm wide; filaments 2.6-
3.0 mm long, purple-blue; anther connective, curved, 1.2-1.3 mm long, 0.4-
0.6 mm wide, purple-blue; with a prominent red gland; anthers pale brownish
yellow; style 3.5-3.8 mm, grey. Fruits 1-5(-7) per inflorescence, reducing in
number at maturity, on stiff pedicels up to 1-4 mm; depressed globose to ob-
late, 6-8 x 3-6 mm diameter, topped by a persistent calycinal crown; surface
smooth, white at immature stage, indigo-blue at partial maturity, then turning
to blackish purple at maturity; cotyledons hardly wrinkled.

Distribution and habitat. Southwestern lowland rainforests of Sri Lanka ex-
cept the coastal zone, in the elevation range 200--500 m (Fig. 3). PDA00002921!
sheet contains information on three localities in Kandy District (the specimens
were mounted by Thwaites in the 1800s). No further collections have been
reported from natural habitats in the surroundings other than from the trees
planted at the Royal Botanical Gardens, Peradeniya. It is thus possible that this
historical gathering information may not relate to this species. Memecylon ros-
tratum is usually confined to the upper level of the rainforest understorey, often
on ridges within a given topography.

Phenology. The main flowering season was reported from March to May,
with fruits produced from May to August. A second season produces flowers
from September to November, with fruits in December to February.

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534 74

Amila Perera et al.: Status of Memecylon elegantulum

Figure 4. Memecylon rostratum Thwaites; A. Habit; B. Outer bark; C. Lamina upper side; D. Lamina under side; E. Flush
leaves; F. Dorsal view of the inflorescence; G. Lateral view of the inflorescence; H. Dorsal view of epigynous chamber
after anthesis; J. Dorsal view of the flower; K. Partially mature fruit; L. Immature fruits; M. Partially mature fruit and
undeveloped fruits; N. Lateral view of flower immediately after anthesis; PR. Cross-section of a partially mature fruit;
Q. Longitudinal section of a partially mature fruit.

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534 45

Amila Perera et al.: Status of Memecylon elegantulum

Figure 5. Line drawing of Memecylon rostratum Thwaites; A. Branch with immature fruits; B. Lamina upper side; C. Lami-
na under side; D. Dorsal view of flower; E. Lateral view of the flower just after anthesis; F. Dorsal view of the flower; G. Dor-
sal view of epigynous chamber after anthesis; H. Partially mature fruit; J. Longitudinal section of a partially mature fruit.

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534 6

Amila Perera et al.: Status of Memecylon elegantulum

Notes. Trimen (1894) mentioned that flowers of Memecylon rostratum are
very pale blue, while Alston (1931), in his key to the species, repeated the same.
The protologue mentioned that the petals were white. This was not necessarily
a misconception: the petals are white while the inside of the hypanthocalyx and
anther connectives are pale blue in this species. This is evident also from the
drawing curated at PDA, which was based on syntypes.

Bremer (1979) lectotypified the name as ‘C.P. 1560 PDA’ while consid-
ering C.P. 1560 in BM, K & US as iso-lectotypes. We found that C.P. 1560
at PDA consisting of two herbarium sheets. PDA00002923! contains four
branchlets with some detached leaves and carries no information about the
gathering. PDA00002921! contains 6 branchlet fragments, one of which re-
tains three attached leaves; the others lack leaves, though the detached
leaves are pasted separately. The branchlet with the leaves has immature
flower buds, while another branchlet that lacks leaves too, bears some
young flower buds. An indistinct pencil notation on this sheet contains in-
formation on three gatherings (Hantana, Gardner; Deltota, in flower; Meda
Mahanuwara, July 1852), though this cannot be explicitly assigned to the
branchlets glued onto the sheet. In any event, because it is composed of
multiple gatherings, Bremer’s lectotypification is incorrect. The present lec-
totype designation rectifies that deficiency and thereby stabilizes the iden-
tity of this species. As in the previous species, we refrain from considering
other C.P. 1560 specimens as iso-lectotypes. Further, we have not included
the C.P. 1560 specimens accessioned in herbaria outside Sri Lanka under
the ‘specimens examined’, pending the availability of magnified images of
the flowers, and since we have encountered similar looking but evidently
undescribed species in the field.

Bremer (1979, 1987) quoted Waas 509 (PDA, US) under this species, which
is a species of Eugenia [probably E. mooniana Wight] (Myrtaceae). The spec-
imens associated with C.P. 2684 and NBK 315 quoted in these publications
(Bremer 1979, 1987) belong to M. elegantulum. The specimens cited as Waas
& Peeris 551 and Cramer 3720 do not exhibit sufficient detail to recognize them
explicitly as Memecylon rostratum.

Specimens examined. ° Sri Lanka: Kandy District: Peradeniya, n.d., F.Fa-
gerlind 4595 (E01411685; US2955736); + Royal Botanic Garden, Peradeni-
ya, 10 iii 1979, Kostermans 27421 (L.2545523, BRO000030741959, PDA[2
sheets]); « ibid., 25 v 1980, Kostermans 28473 (L.2545522); « ibid., 13 ii 1904,
C.C.Hosseus 12 (M0168532); + ibid., 2022 ix 16, H.Jayasinghe HDJ 1693
(PDA); : ibid., 1964 v 26, D.Amaratunga 818 (PDA); « ibid., 1955 v 30, T.B. Worth-
ington 6746 (PDA Ratnapura District: Sinharaja forest, between Heend Dola
& Gallen Dola, 1989 iv 26, A.H.M.Jayasuriya & S.Balasubramaniam 4697
(PDA); * Mulawella trail, Sinharaja, 2023 v 03, H.Jayasinghe & D.Samaras-
inghe HDJ 2197 (PDA); Walankanda, 2 v 1976, S.Waas 1557 (E01411686,
L.2545521, PDA [2 sheets]) + Kalutara District: East Kalugala Forest, 1 v
1976, S.Waas 1534 (E01411684, L.2545520, PDA [2 sheets]) * Galle District:
Kanneliya forest near Hiniduma, 7 vi 1973, Kostermans 24727 (L.2545524,
US2955733); * ibid., 25 vii 1976, A.H.M.Jayasuriya & A.J.Kostermans 2371
(P05255614, PDA); « Kalubowitiyana, 2023 xi 06, H.Jayasinghe, D.Dhanush-
ka, S.Kanishka & D.Samarasinghe HDJ 2557 (PDA); * Opatha, 2024 v 05, H.
Jayasinghe, D.Samarasinghe, A.Perera, PJayasundara HDJ 30617 (PDA).

PhytoKeys 259: 67-80 (2025), DOI: 10.3897/phytokeys.259.146534 os

Amila Perera et al.: Status of Memecylon elegantulum

Acknowledgements

We thank our field crew for their dedicated support: including Thilina Abeykoon,
Dhananjaya Perera, Dilum Samarasinghe, Dineth Danushka, Suneth Kanishka, T.
Pathmanadan, R. Chandrakumar, and R. Upul. Isuru Kariyawasam commented
on an earlier version of this manuscript; Lasith Siriwardana assisted with draw-
ings; and Dushan Kumarathunga guided the planning of our floristics survey of
Walankanda Forest Reserve.

The National Herbarium (Department of National Botanic Gardens) permit-
ted the examination of voucher specimens. We gratefully acknowledge the
management of Endana Estate and Kahawatta Plantations PLC for the provi-
sion of facilities for fieldwork.

The Forest Department and the Department of Wildlife Conservation of Sri Lan-
ka granted research permissions, and their field officers assisted in field surveys.

Additional information

Conflict of interest

The authors have declared that no competing interests exist.

Ethical statement

No ethical statement was reported.

Funding

Financial support for this research was provided by Dilmah Conservation of Dilmah Cey-
lon Tea PLC and the Franklinia Foundation, Switzerland (Grant No: 2021-05). The Botanical
Survey project, funded by the Trust Fund of the Department of National Botanic Gardens,
enabled the field work of BG. Rajarata University of Sri Lanka assisted the work of NG.

Author contributions

Conceptualization, data curation and analysis: AP HJ, IM, NaG; fund acquisition, project
administration and supervision: NaG, NiG, HJ; investigation, methodology, and visualiza-
tion: AP, HJ, BG, IM; writing and editing: all authors.

Author ORCIDs

Amila Perera © https://orcid.org/0000-0002-7045-0790
Himesh Jayasinghe © https://orcid.org/0000-0001-5308-9158
Bhathiya Gopallawa © https://orcid.org/0000-0003-4293-7988
Isuru Madawala © https://orcid.org/0000-0002-0462-9426
Nimal Gunatilleke © https://orcid.org/0000-0003-3271-2945
Nalaka Geekiyanage © https://orcid.org/0000-0002-7400-3453

Data availability
All of the data that support the findings of this study are available in the main text.
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